<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .parent {
        width: 500px;
        height: 500px;
        display: grid;
        grid-template-columns: minmax(150px, 25%) 1fr;
      }
      .child1 {
        height: 100%;
        background-color: rgb(19, 75, 150);
      }
      .child2 {
        height: 100%;
        background-color: rgb(3, 20, 5);
      }
    </style>
  </head>
  <body>
    <div class="parent">
      <div class="child1"></div>
      <div class="child2"></div>
    </div>
  </body>
</html>
